Thank you greg, my viewpoint for the question was a bit different. Considering that the blockchains are inherently open in nature, is it possible to index every file that is being added into IPFS ? What would be the entry point for it ? I am trying to understand if vulnerability like this exists.
– okpDec 14 '18 at 4:47

Not sure to understand your point. But yeah you can index your files (hash) on the Ethereum blockchain which would be as you mentionned public. The entry point would be a smart contract (if it's what you're asking). In terms of vulnerabilities in this pattern (store file on IPFS and index on Ethereum), I think the risk is more on the IPFS side, if your file isn't replicated (pinned) on the IPFS network and you lost your unique node, nobody would be able to get the file.
– Greg JeanmartDec 14 '18 at 9:05